It is known to use an optical time-domain reflectometer (OTDR) in the form of a standalone optoelectronic test instrument to characterize an optical fiber. The OTDR injects a series of optical pulses into an optical fiber under test, and detects light that is Rayleigh scattered and reflected back from locations in the fiber where the fiber's index of refraction changes. The return pulses are, for example, measured and integrated as a function of time, and can be plotted as a function of fiber length. Such an OTDR may be used for estimating a fiber's length and overall attenuation, including indicating splice and connection losses, for example. The OTDR can also be used to locate faults, such as breaks, in the fiber. It is also known to provide small form factor fiber-optic transceiver modules having built-in test capability.